FindAndDelete again.

lib/bcoin/script.js

@@ -2026,6 +2026,77 @@ Script.prototype.removeData = function removeData(data) {
   return index.length;
 };
 
+/**
+ * A more accurate, but slower implementation
+ * of FindAndDelete. Shouldn't be necessary
+ * in practice.
+ * @private
+ * @param {Buffer} data
+ * @returns {Buffer}
+ */
+
+Script.prototype.findAndDelete = function findAndDelete(data) {
+  var total = 0;
+  var p, raw, a, b, op, size;
+
+  if (data.length === 0)
+    return total;
+
+  // Compare on the byte level.
+  raw = this.encode();
+
+  p = new BufferReader(raw, true);
+
+  for (;;) {
+    while (p.left() >= data.length && utils.icmp(raw, data, p.offset) === 0) {
+      a = raw.slice(0, p.offset);
+      b = raw.slice(p.offset + data.length);
+      raw = Buffer.concat([a, b]);
+      p.data = raw;
+      total++;
+    }
+
+    if (p.left() === 0)
+      break;
+
+    op = p.readU8();
+    if (op >= 0x01 && op <= 0x4b) {
+      if (p.left() < op)
+        break;
+      p.seek(op);
+    } else if (op === opcodes.OP_PUSHDATA1) {
+      if (p.left() < 1)
+        break;
+      size = p.readU8();
+      if (p.left() < size)
+        break;
+      p.seek(size);
+    } else if (op === opcodes.OP_PUSHDATA2) {
+      if (p.left() < 2)
+        break;
+      size = p.readU16();
+      if (p.left() < size)
+        break;
+      p.seek(size);
+    } else if (op === opcodes.OP_PUSHDATA4) {
+      if (p.left() < 4)
+        break;
+      size = p.readU32();
+      if (p.left() < size)
+        break;
+      p.seek(size);
+    }
+  }
+
+  if (total > 0) {
+    this.code = Script.decode(raw);
+    if (this.raw)
+      this.raw = raw;
+  }
+
+  return total;
+};
+
 /**
  * Find a data element in a script.
  * @param {Buffer} data - Data element to match against.
@@ -4169,6 +4240,37 @@ Script.encode = function encode(code, writer) {
   return p;
 };
 
+/**
+ * Encode a single push op. Note that this
+ * will _always_ be a PUSHDATA. Used for
+ * findAndDelete.
+ * @param {Buffer} data
+ * @returns {Buffer}
+ */
+
+Script.encodePush = function encodePush(data) {
+  var p = new BufferWriter();
+  if (data.length <= 0x4b) {
+    p.writeU8(data.length);
+    p.writeBytes(data);
+  } else if (data.length <= 0xff) {
+    p.writeU8(opcodes.OP_PUSHDATA1);
+    p.writeU8(data.length);
+    p.writeBytes(data);
+  } else if (data.length <= 0xffff) {
+    p.writeU8(opcodes.OP_PUSHDATA2);
+    p.writeU16(data.length);
+    p.writeBytes(data);
+  } else if (data.length <= 0xffffffff) {
+    p.writeU8(opcodes.OP_PUSHDATA4);
+    p.writeU32(data.length);
+    p.writeBytes(data);
+  } else {
+    assert(false, 'Bad pushdata op.');
+  }
+  return p.render();
+};
+
 /**
  * Determine whether GetOp2 should fail
  * on a given op due to a bad push (either

test/script-test.js

@@ -352,4 +352,157 @@ describe('Script', function() {
       });
     });
   });
+
+  it('should execute FindAndDelete correctly', function() {
+    var s, d, expect;
+
+    function del(s) {
+      s.mutable = true;
+      delete s.raw;
+      return s;
+    }
+
+    s = bcoin.script.fromString('OP_1 OP_2');
+    del(s);
+    d = new bcoin.script();
+    expect = s.clone();
+    assert.equal(s.findAndDelete(d.encode()), 0);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromString('OP_1 OP_2 OP_3');
+    del(s);
+    d = bcoin.script.fromString('OP_2');
+    del(d);
+    expect = bcoin.script.fromString('OP_1 OP_3');
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 1);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromString('OP_3 OP_1 OP_3 OP_3 OP_4 OP_3');
+    del(s);
+    d = bcoin.script.fromString('OP_3');
+    del(d);
+    expect = bcoin.script.fromString('OP_1 OP_4');
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 4);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('0302ff03', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('0302ff03', 'hex');
+    del(d);
+    expect = new bcoin.script();
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 1);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('0302ff030302ff03', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('0302ff03', 'hex');
+    del(d);
+    expect = new bcoin.script();
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 2);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('0302ff030302ff03', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('02', 'hex');
+    del(d);
+    expect = s.clone();
+    del(expect);
+    //assert.equal(s.findAndDelete(d.encode()), 0);
+    s.findAndDelete(d.encode());
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('0302ff030302ff03', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('ff', 'hex');
+    del(d);
+    expect = s.clone();
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 0);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('0302ff030302ff03', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('03', 'hex');
+    del(d);
+    expect = new bcoin.script([new Buffer([0xff, 0x03]), new Buffer([0xff, 0x03])]);
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 2);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('02feed5169', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('feed51', 'hex');
+    del(d);
+    expect = s.clone();
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 0);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('02feed5169', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('02feed51', 'hex');
+    del(d);
+    expect = bcoin.script.fromRaw('69', 'hex');
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 1);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('516902feed5169', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('feed51', 'hex');
+    del(d);
+    expect = s.clone();
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 0);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('516902feed5169', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('02feed51', 'hex');
+    del(d);
+    expect = bcoin.script.fromRaw('516969', 'hex');
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 1);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromString('OP_0 OP_0 OP_1 OP_1');
+    del(s);
+    d = bcoin.script.fromString('OP_0 OP_1');
+    del(d);
+    expect = bcoin.script.fromString('OP_0 OP_1');
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 1);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromString('OP_0 OP_0 OP_1 OP_0 OP_1 OP_1');
+    del(s);
+    d = bcoin.script.fromString('OP_0 OP_1');
+    del(d);
+    expect = bcoin.script.fromString('OP_0 OP_1');
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 2);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('0003feed', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('03feed', 'hex');
+    del(d);
+    expect = bcoin.script.fromRaw('00', 'hex');
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 1);
+    assert.deepEqual(s.encode(), expect.encode());
+
+    s = bcoin.script.fromRaw('0003feed', 'hex');
+    del(s);
+    d = bcoin.script.fromRaw('00', 'hex');
+    del(d);
+    expect = bcoin.script.fromRaw('03feed', 'hex');
+    del(expect);
+    assert.equal(s.findAndDelete(d.encode()), 1);
+    assert.deepEqual(s.encode(), expect.encode());
+  });
 });